Question

Driving along a boring stretch of interstate in Illinois, you start experimenting using the average speed equation you learned in class. You drive 29 meters per second for 120s, then 35 meters per second for 300s. Then you entertain yourself by determining your average speed during those time intervals. What is your average speed for the experiment?

Answer 1

The average speed would be 33.29m/s.
The average speed equation is:

$Average speed = \frac{total distance}{total time}$

First you will need to solve for the distance you traveled in each scenario. So we can solve this by getting the product of speed and the time traveled. 

Scenario 1:
Speed = 29m/s
Time = 120s
Distance = ?

Distance = (29m/s)(120s)
               = 3,480m

Scenario 2
Speed = 35m/s
Time = 300s
Distance = ? 

Distance = (35m/s)(300s)
               = 10,500m

Now that you have the distance of both, you can solve for your average speed. 

$Average speed = \frac{total distance}{total time}$
                                $= \frac{3,480m+10,500m}{120s+300s}$
                                $= \frac{13,980m}{420s}$
                                $= 33.29m/s$